| >>Note: Nutrition is a science that examines the relationship between diet and health. Dietitians are health professionals who specialize in this area of study, and are trained to provide safe, evidence-based dietary advice and interventions. Deficiencies, excesses and imbalances in diet can produce negative impacts on health, which may lead to diseases such as cardiovascular disease, diabetes, scurvy, obesity or osteoporosis. Many common diseases and their symptoms can often be prevented or alleviated with better nutrition. The science of nutrition attempts to understand how and why specific dietary aspects influence health. [http://en.wikipedia.org/wiki/Nutrition] |
| | >>Note: Nutrition science investigates metabolic and physiological responses of the body to diet. With advances in molecular biology, biochemistry, and genetics, nutrition science is additionally developing into the study of metabolism, which seeks to disconnect diet and health through the lens of biochemical processes. [http://en.wikipedia.org/wiki/Nutrition#Overview] |
| | >>Note: There are seven main classes of nutrients that the body needs: carbohydrates, proteins, fats, vitamins, minerals, fibre and water. It is important to consume these seven nutrients on a daily basis to build and maintain health. [http://en.wikipedia.org/wiki/Nutrition#Nutrients] |
| | Polyunsaturated fatty acids |
| | >>Note: Polyunsaturated fat, along with monounsaturated fat are "healthy fats," the amount of which in one's daily diet should be near 25 g (in a 2000 calorie-per-day diet). Polyunsaturated fat can be found mostly in grain products, fish and sea food (herring, salmon, mackerel, halibut), soybeans, and fish oil. Foods like mayonnaise and soft margarine may also be good sources, but nutritional facts can vary by style and brand. Omega-3 fatty acids in fish oil, fish and seafood lower the total amount of fat in the blood, which can lower blood pressure and decrease the risk of cardiovascular diseases. Omega-6 fatty acids in sunflower oil and safflower oil also reduce the risk of cardiovascular disease, but can contribute to allergies and inflammation. Polyunsaturated fat may lower LDL and HDL cholesterol. [http://en.wikipedia.org/wiki/Polyunsaturated_fat#Benefits] |
| | >>Note: Trans fat is the common name for a type of unsaturated fat with trans isomer fatty acid(s). Trans fats may be monounsaturated or polyunsaturated. Most trans fats consumed today are industrially created by partially hydrogenating plant oils — a process developed in the early 1900s and first commercialized as Crisco in 1911. The goal of partial hydrogenation is to add hydrogen atoms to unsaturated fats, making them more saturated. These more saturated fats have a higher melting point making them attractive for baking, and extending their shelf-life. Another particular class of trans fats, vaccenic acid occurs in trace amounts in meat and dairy products from ruminants. Unlike other dietary fats, trans fats are neither required nor beneficial for health. Eating trans fats increases the risk of coronary heart disease. Trans fat raises your ("bad") LDL cholesterol and lowers your ("good") HDL cholesterol. Health authorities worldwide recommend that consumption of trans fat be reduced to trace amounts. Trans fats from partially hydrogenated oils are generally considered to be more of a health risk than naturally occurring oils. [http://en.wikipedia.org/wiki/Trans_fat] |
| | >>Note: Fats are composed of fatty acids, long carbon/hydrogen chains bonded to a glycerol. Fat may be classified as saturated or unsaturated. Saturated fats have all of their carbon atoms bonded to hydrogen atoms, whereas unsaturated fats have some of their carbon atoms double-bonded in place of a hydrogen atom. Generally, saturated fat is solid at room temperature while unsaturated fat is a liquid. Unsaturated fats may be further classified as mono-unsaturated (one double-bond) or poly-unsaturated (many double-bonds). Trans fats are saturated fats which are typically created from unsaturated fat by adding the extra hydrogen atoms in a process called hydrogenation (also called hydrogenated fat). Most fatty acids are non-essential, meaning the body can produce them as needed, however, at least two fatty acids are essential and must be consumed in the diet. An appropriate balance of essential fatty acids - omega-3 and omega-6 fatty acids - has been discovered to be crucial for maintaining health. [http://en.wikipedia.org/wiki/Nutrition#Fat] |
| | >>Note: Mineral and/or vitamin deficiency or excess may yield symptoms of diminishing health such as goitre, scurvy, osteoporosis, weak immune system, disorders of cell metabolism, certain forms of cancer, symptoms of premature aging, and poor psychological health (including eating disorders), among many others. [http://en.wikipedia.org/wiki/Nutrition#Vitamins] |
| | >>Note: Protein is composed of amino acids, that are body's structural(muscles, skin, hair etc.) materials. The body requires amino acids to produce new body protein (protein retention) and to replace damaged proteins (maintenance) that are lost in the urine. In animals amino acid requirements are classified in terms of essential (an animal cannot produce them) and non-essential (the animal can produce them from other nitrogen containing compounds) amino acids. Consuming a diet that contains adequate amounts of essential (but also non-essential) amino acids is particularly important for growing animals, who have a particularly high requirement. Dietary sources of protein include meats, eggs, grains, legumes, and dairy products such as milk and cheese. Proteins can be converted into carbohydrates through a process called gluconeogenesis. [http://en.wikipedia.org/wiki/Nutrition#Protein] |
| | >>Note: Dietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen which are present in common organic molecules. The term "mineral" is archaic, since the intent of the definition is to describe ions, not chemical compounds or actual minerals. Some dietitians recommend that these heavier elements should be supplied by ingesting specific foods (that are enriched in the element(s) of interest), compounds, and sometimes including even minerals, such as calcium carbonate. Sometimes these "minerals" come from natural sources such as ground oyster shells. Sometimes minerals are added to the diet separately from food, such as mineral supplements, the most famous being iodine in "iodized salt." [http://en.wikipedia.org/wiki/Nutrition#Minerals] |
| | >>Note: Carbohydrates may be classified as monosaccharides, disaccharides, or polysaccharides by the number of sugar units they contain. Monosaccharides contain 1 sugar unit, disaccharides contain 2, and polysaccharides contain 3 or more. Polysaccharides are often referred to as complex carbohydrates because they are long chains of sugar units, whereas monosaccharides and disaccharides are simple carbohydrates. The difference is important to nutritionists because complex carbohydrates take longer to metabolize since their sugar units are processed one-by-one off the ends of the chains. Simple carbohydrates are metabolized quickly and thus raise blood sugar levels more quickly resulting in rapid increases in blood insulin levels. [http://en.wikipedia.org/wiki/Nutrition#Carbohydrates] |
| | >>Note: Dietary fibre consists mainly of cellulose that is indigestible because we do not have enzymes to digest it.Fruits and vegetables are rich in dietary fibre. Importance of dietary fibre: 1) provides bulk to the intestinal contents; 2) stimulates peristalsis(rhytmic muscular contractions passing along the digestive tract) lack of dietary fibre in the diet leads to constipation (failure to pass motions). [http://en.wikipedia.org/wiki/Nutrition#Fiber] |
| | >>Note: About 70% of the non-fat mass of the human body is made of water. To function properly, the body requires between one and seven liters of water per day to avoid dehydration; the precise amount depends on the level of activity, temperature, humidity, and other factors. With physical exertion and heat exposure, water loss will increase and daily fluid needs may increase as well. Normally, about 20% of water intake comes from food, while the rest comes from drinking water and beverages (caffeinated included). Water is excreted from the body in multiple forms; through urine and feces, through sweating, and by exhalation of water vapor in the breath. [http://en.wikipedia.org/wiki/Nutrition#Water] |
| | Intestinal bacterial flora |
| | >>Note: It is now also known that the human digestion system contains a population of a range of bacteria and yeast such as Bacteroides, L. acidophilus and E. coli which are essential to digestion, and which are also affected by the food we eat. Bacteria in the gut fulfill a host of important functions for humans, including breaking down and aiding in the absorption of otherwise indigestible food; stimulating cell growth; repressing the growth of harmful bacteria, training the immune system to respond only to pathogens; and defending against some diseases. [http://en.wikipedia.org/wiki/Nutrition#Intestinal_bacterial_flora] |
| | >>Note: Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals. Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect. [http://en.wikipedia.org/wiki/Nutrition#Antioxidants] |
| | >>Note: A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, antioxidant nutrients typically found in edible plants, especially colorful fruits and vegetables. The effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease. [http://en.wikipedia.org/wiki/Nutrition#Phytochemicals] |
| | >>Note: The protein requirements of athletes, once the source of great controversy, has settled into a current consensus. Sedentary people and recreational athletes have similar protein requirements, about 1 gram of protein per kilogram of body mass. These needs are easily met by a balanced diet containing about 70 grams of protein for a 70 kg (150 pound) man or 60 grams of protein for a 60 kg (130 pound) woman. People who exercise at greater intensity, and especially those whose activity grows muscle bulk, have significantly higher protein requirements. According to Clinical Sports Nutrition , active athletes playing power sports (such as football), those engaged in muscle-development training, and elite endurance athletes, all require approximately 2 grams of protein per day per kilogram of body weight, roughly double that of a sedentary persons. Older athletes seeking primarily to maintain developed muscle mass require 2 to 3 g/day/kg. Protein intake in excess of that required to build muscle (and other) tissue is broken-down by gluconeogenesis to be used as energy. The most recent evidence appears to support the beneficial nature of a high-protein, low-carbohydrate diet. [http://en.wikipedia.org/wiki/Nutrition#Protein_2] |
| | >>Note: Maintaining hydration during periods of physical exertion is key to good performance. While drinking too much water during activities can lead to physical discomfort, dehydration in excess of 2% of body mass (by weight) markedly hinders athletic performance. It is recommended that an athlete drink about 400-600 mL 2-3 hours before activity, during exercise he or she should drink 150-350mL every 15 to 20 minutes and after exercise that he or she replace sweat loss by drinking 450-675 mL for every 0.5 kg body weight loss during activity. Some studies have shown that an athlete that drinks before they feel thirsty stays cooler and performs better than one who drinks on thirst cues, although recent studies of such races as the Boston Marathon have indicated that this recommendation can lead to the problem of overhydration. Additional carbohydrates and protein before, during, and after exercise increase time to exhaustion as well as speed recovery. Dosage is based on work performed, lean body mass, and environmental factors, especially ambient temperature and humidity. Excess water intake, without replenishment of sodium and potassium salts, leads to hyponatremia, which can further lead to water intoxication at more dangerous levels. [http://en.wikipedia.org/wiki/Nutrition#Water_and_Salts] |
| | >>Note: The main fuel used by the body during exercise is carbohydrates, which is stored in muscle as glycogen- a form of sugar. During exercise, muscle glycogen reserves can be used up, especially when activities last longer than 90 min. When glycogen is not present in muscles, the muscle cells perform anaerobic respiration producing lactic acid, which is responsible for fatigue and burning sensation, and post exercise stiffness in muscles. Because the amount of glycogen stored in the body is limited, it is important for athletes to replace glycogen by consuming a diet high in carbohydrates. Meeting energy needs can help improve performance during the sport, as well as improve overall strength and endurance. [http://en.wikipedia.org/wiki/Nutrition#Carbohydrates_2] |
| | >>Note: Heart disease, cancer, obesity, and diabetes are commonly called "Western" diseases because these maladies were once rarely seen in developing countries. One study in China found some regions had essentially no cancer or heart disease, while in other areas they reflected “up to a 100-fold increase” coincident with diets that were found to be entirely plant-based to heavily animal-based, respectively. In contrast, diseases of affluence like cancer and heart disease are common throughout the United States. Adjusted for age and exercise, large regional clusters of people in China rarely suffered from these “Western” diseases possibly because their diets are rich in vegetables, fruits and whole grains. [http://en.wikipedia.org/wiki/Nutrition#Whole_plant_food_diet] |
| | >>Note: It has been discovered that people living in France live longer. Even though they consume more saturated fats than Americans, the rate of heart disease is lower in France than in North America. A number of explanations have been suggested: 1) Reduced consumption of processed carbohydrate and other junk foods; 2) Ethnic genetic differences allowing the body to be harmed less by fats; 3) Regular consumption of red wine; 4) Living in the South requires the body to produce less heat, allowing a slower, and therefore healthier, metabolic rate. 5) More active lifestyles involving plenty of daily exercise, especially walking; the French are much less dependent on cars than Americans are. However, a growing number of French health researchers doubt the theory that the French are healthier than other populations. Statistics collected by the WHO from 1990-2000 show that the incidence of heart disease in France may have been underestimated and in fact be similar to that of neighboring countries. [http://en.wikipedia.org/wiki/Nutrition#The_French_.22paradox.22] |
| | >>Note: Research indicates that improving the awareness of nutritious meal choices and establishing long-term habits of healthy eating has a positive effect on a cognitive and spatial memory capacity, potentially increasing a student’s potential to process and retain academic information. [http://en.wikipedia.org/wiki/Nutrition#Mental_agility] |
| | >>Note: Lifestyle- and obesity-related diseases are becoming increasingly prevalent all around the world. There is little doubt that the increasingly widespread application of some modern food processing technologies has contributed to this development. The food processing industry is a major part of modern economy, and as such it is influential in political decisions (e.g. nutritional recommendations, agricultural subsidising). In any known profit-driven economy, health considerations are hardly a priority; effective production of cheap foods with a long shelf-life is more the trend. In general, whole, fresh foods have a relatively short shelf-life and are less profitable to produce and sell than are more processed foods. Thus the consumer is left with the choice between more expensive but nutritionally superior whole, fresh foods, and cheap, usually nutritionally inferior processed foods. Because processed foods are often cheaper, more convenient (in both purchasing, storage, and preparation), and more available, the consumption of nutritionally inferior foods has been increasing throughout the world along with many nutrition-related health complications. |
| | [http://en.wikipedia.org/wiki/Nutrition#Processed_foods] |
| | >>Note: The development of transgenic crops (genetically modified crops) might be an extremely important concept for the future. Malnutrition and disease are very common problems faced by people in less developed countries. Through manipulation of these crops, it could be possible to engineer a crop that has certain disease fighting properties in addition to providing essential nutrients to the people who eat them. However, the possible negative effects of these crops is largely unexplored but could include dangerous allergic reactions or other biochemical incompatibility issues. The seemingly long list of both positive and negative effects of transgenic crops makes it important to continue doing research in the field of genetics. [http://en.wikipedia.org/wiki/Nutrition#Transgenic_Crops] |
| | >>Note: Humans have evolved as omnivorous hunter-gatherers over the past 250,000 years. The diet of early modern humans varied significantly depending on location and climate. The diet in the tropics tended to be based more heavily on plant foods, while the diet at higher latitudes tended more towards animal products. Analysis of postcranial and cranial remains of humans and animals from the Neolithic, along with detailed bone modification studies have shown that cannibalism was also prevalent among prehistoric humans. Agriculture developed about 10,000 years ago in multiple locations throughout the world, providing grains such as wheat, rice, and maize, with staples such as bread and pasta. Farming also provided milk and dairy products, and sharply increased the availability of meats and the diversity of vegetables. The importance of food purity was recognized when bulk storage led to infestation and contamination risks. Cooking developed as an often ritualistic activity, due to efficiency and reliability concerns requiring adherence to strict recipes and procedures, and in response to demands for food purity and consistency. [http://en.wikipedia.org/wiki/Nutrition#History] |
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